Telescopic position adjusting devices

ABSTRACT

An aircraft seat having an angularly adjustable back and a telescopic position adjusting device arranged to hold the seat back in any position to which it is set. The telescopic position adjusting device comprises a hollow plunger slidable in a closed ended cylinder. A floating piston divides the hollow plunger into two chambers one of which is filled with liquid and communicates with a passage in the closed end of the cylinder via the bore of a tubular stem which projects through an aperture in the plunger end wall. The other chamber is filled with compressed gas. A nonreturn valve controls liquid flow through the passage between the tubular stem bore and the liquid filled annular cylinder space surrounding the tubular stem. The non-return valve is spring closed and may be opened manually by a pin which is housed within the closed end of the cylinder for movement radially of the cylinder. The tubular stem has a radial flange which is engaged by a clip ring mounted in the cylinder and held in abutment with the closed end of the cylinder. The stroke of movement of the plunger can be altered by an adjustable sleeve which provides a stop surface for engagement by the plunger at one end of its stroke.

[ TELESCOPIC POSITION ADJUSTING DEVICES Inventor: Wilfred NicholasBainbridge,

lleamington Spa, England [73] Automotive Products Company Limited,Leamington Spa,

Warwickshire, England Filed: June 15, 1971 Appl. No.: 153,227

Assignee:

1 June 19, 1973 and a telescopic position adjusting device arranged tohold the seat back in any position to which it is set. The

telescopic position adjusting device comprises a hollow plunger slidablein a closed ended cylinder. A floating piston divides the hollow plungerinto two chambers one of which is filled with liquid and communicateswith a passage in the closed end of the cylinder via the bore of atubular stem which projects through an aperture in the plunger end wall.The other chamber is filled Cl 188/306 248/354 H, 297/355 withcompressed gas. A non-return valve controls liq- 51 1m. 01. Fl6d 63/00thmugh the Passage hetweeh the tubular stem [58] Field of Search188/289, 300, 314, bore and the liquid filled annular cylihder Space 1188/322. 248/354 H; 297/355 rounding the tubular stem. The nonreturnvalve is spring closed and may be opened manually by a pin [56]References Cited which is housed within the closed end of the cylinderUNITED STATES PATENTS for movement radially of the cylinder. The tubularstem has a radial flange which is engaged by a clip ring 3,356,18612/1967 Lambers 188/300 X mounted in the cylinder and held in abutmentwith the closed end of the cylinder. The stroke of movement of 347ll4010/1969 Ballard Ab the plunger can be altered by an adjustable sleeve "Twhich provides a stop surface for engagement by the PrimaryExaminer-George E. A. Halvosa plunger at one end of Its StrokeAttorney-Lawrence J. Winter 5 Claims, 3 Drawing Figures 33 43 5 8 124 Qs 1 b 1' 7 39 49 36 0 45 l 2 E {Y 47 1 l l 25 53 15 52 15 34l 42 4aPAIENIEB 191975 3.739.885

' saw 1 or 2 y WZ 14 TORNEY 1 TELESCOPIC POSITION ADJUSTING DEVICES Thisinvention relates to telescopic position adjusting devices such as areused, for example, to hold the angularly adjustable backs of seats inaircraft and vehicles inany position to which they are set, the saidadjusting devices including energy storing means providing a forcetending to urge the seat back or other component with which the deviceis used to one of its extreme positions and locking means normallypreventing move ment of the said seat back or other componentby saidforce or by external acting forces normally applied thereto during use.The telescopic position adjusting device according to the inventioncomprises a cylinder having a closed end and an open end, a hollowplunger slidable in said cylinder, the said plunger having an aperturedend wall facing the closed end of the cylinder and being closed at itsother end, a tubular stem mounted in said cylinder and extending throughthe aperture in the end wall of the plunger, a floating piston slidablein said hollow plunger and dividing the interior thereof into first andsecond chambers respectively between the said floating piston and theclosed end of the plunger and between the floating piston and saidapertured end wall, the said floating piston being urged by resilientmeans in said first chamber towards said apertured end wall, passagemeans in the closed end of the cylinder connecting the said secondchamber through the bore of the tubular stem, to the annular space inthe cylinder between the closed end thereof and the apertured end wallof the plunger, said second chamber and annular space being adapted tobe filled with liquid, a non-return valve operative to prevent flow ofliquid through said passage means and the bore of said tubular stem fromsaid annular space intosaid second chamber and spring loaded to resistflow of liquid in the opposite direction, and externally operable meansfor opening said nonreturn valve.

The tubular stem may be formed at one end with an annular externalflange which is held by retaining means against the closed end of thecylinder, and may carry stop means limiting outward movement of theplunger.

Stroke adjusting means may be provided for limiting the stroke of theplunger.

The stroke adjusting means may comprise a sleeve surrounding and havingscrew-threaded engagement with the cylinder and an annular stop surfaceon the plunger to co-operate with the end of said sleeve, releasablelocking means being provided to hold the sleeve against rotation;

Alternatively, the stroke adjusting means may comprise a sleeve axiallymovable with one of the relatively axially movable members constitutedby the cylinder and plunger and having a stepped aperture therein, aradial projection on the other of said members extending into saidaperture, and means for selectively positioning said sleeve in therotational sense to align the radial projection with any one of thesteps in the aperture.

The resilient means in said first chamber may comprise compressed gas.

There will now be described, by way of example, one embodiment of atelescopic position adjusting device according to the invention,reference being made in the description to the accompanying drawings, inwhich:

F IG. 1 is a diagrammatic side elevation of a seat, such as an aircraftseat, having an angularly adjustable back the position of which isadjustable by means of a device according to the invention;

FIG. 2 is a sectional elevation of one form of telescopic positionadjusting device according to the invention;

FIG. 3 is a plan view of a telescopic position adjusting device as shownin FIG. 2 but having a modified form of stroke adjusting means.

Referring to FIG. 1 of the drawings a seat frame 10 supports a seatcushion 11, and a seat back 12 is pivotally mounted at 13 on the frame10 so as to be angularly' adjustable, the said seat back having securedto it an arm 14 depending below the pivot at 13. A telescopic positionadjusting device 15 for providing angular adjustment of the seat back 12comprises a cylinder 16 pivoted to the arm 14 and a plunger 17 pivotedto an anchorage 18 on the seat frame, so that movement of the seat backtowards an upright position is accompanied by outward movement of theplunger 17 in the cylinder 16 and movement of the seat back towards areclining position is accompanied by inward movement of the plunger 17with respect to the cylinder 16. A valve in the telescopic positionadjusting device 15, the purpose of which will be hereinafter described,is controlled, through a liquid pressure control system of thehydrostatic type including a master cylinder 19 connected, by a conduit20, to a slave cylinder 20a for operating the said valve, the mastercylinder being operated by a push button 21 mounted on the seat frame10.

Referring now to FIG. 2, the cylinder 16 of the telescopic positionadjusting device 15 is closed at one end by a head member 22conveniently integral with the cylinder 16, and is open at its otherend, the plunger 17, which is hollow being slidable in the cylinder 16and projecting from the open end thereof. The plunger 17, at its endwhich lies inside the cylinder 16, has an end wall 23 formed with acentral aperture 24. The bore of the plunger 17 is closed at its otherend, for example, as shown in the drawing, by a screw plug 25, thecylinder head member 22 and the screw plug 25 being arranged for pivotalattachment to members such as the arm 14 and anchorage 18 shown in FIG.1, between which the position adjusting device is mounted for use.

A floating piston 26 is mounted in the bore of the plunger 17 andcarries a packing ring 27 engaging the wall of the plunger, thusdividing the interior of the plunger into first and second chambers 28and 29.

A tubular stem 31, having an external radial flange 32 at one end, ismounted in the cylinder 16 so as to project through the central aperture24 in the plunger end wall 23, the said stem 31 engaging a packing ring33 mounted in the said aperture 24. The radial flange 32 on the stem isheld, for example by a clip ring 34, against the inner face of thecylinder head member 22 and another clip ring 35 or equivalent devicemounted on the other endof the tubular stem 31 provides a stop limitingoutward movement of the plunger 17.

A diametral bore 36 in the cylinder head is connected by a central axialbore 37 in the said cylinder head member 22 to the bore 38 of thetubular stem 31,

and a packing ring 39, mounted in an annular groove in the flange 32 ofthe said stern provides a fluid-tight connection between said axial bore37 and the bore 38 of the stem. On the radially outer side of the saidpacking ring 39 the face of the flange is relieved as shown at 41, and afurther bore 42 in the cylinder head member, connected to the diametralbore 36, opens in the inner face of the head member 22 opposite therelieved portion 41 of the flange, thus communicating with the annularspace 43 in the cylinder 16 around the tubular stem 31. v I

A seat 44is provided in the diametral bore 36 between the positions atwhich the axial bore 37 and the further bore 42 open thereinto, the saidseat being conveniently formed in a plug 45 located against a shoulder46 in the bore, and a ball 47, urged by a coiled comvalve ball 47 toallow extension by the force exerted by pression spring 48 towards theseat 44, acts as a nonreturn valve preventing flow of liquid from saidfurther bore 42 to the axial bore 37 and as a check valve resisting flowin the opposite direction. The ball 47, when seated, thus prevents flowof liquid from the annular space 43 into the plunger chamber 29, andprovides resistance to flow of liquid from the plunger chamber 29 intothe annular space 43.

Externally operable means, shown as a pin 49 guided in a tubular plug 50screwed into one end of the diametral bore 36 are arranged to push theball 47 off the seat 44 and thus provide free communication between theannular space 43 and the plunger chamber 29. The pin 49 is operable froma remote position by the'push button 21 and liquid pressure controlsystem shown in FIG. 1, or may be similarly operable by other means suchas a Bowden cable. 1

One or more radial bores 51, of very small diameter, for example a fewthousandths of an inch, are formed in the tubular stem 31 to connect thebore 38 thereof to the annular space 43 in the cylinder around the saidstem, the said bore or bores 51 being so positioned that, when the stop35 limiting outward movement of the plunger 17 is in engagement with theplunger end wall 23, they are just clear of the packing ring 33 mountedin the said end wall, on the side of the said packing ring nearer to theannular space 43.

The maximum stroke of the plunger 17 is determined by the length of thetubular stem 31, and the said stroke may be reduced by a screw-threadedsleeve 52 mounted externally on the cylinder 16 and cooperating with anabutment shoulder 53 on the plunger 17, the sleeve 52 being held againstundesired rotation by a ball detent 54 mounted in a hole in the sleeveand urged inwardly by a circumferential spring clip 55 to engage in alongitudinal groove 56 in the cylinder wall.

To prepare the position adjusting device for use, liquid is inserted inthe annular space 43 in the cylinder and in the chamber 29 in theplunger, the quantity of liquid being sufficient to position thefloating piston 26, 4

as shown in FIG. 2, at a short distance from the inner end of theplunger 17 when the device is fully extended, and compressed gas,preferably nitrogen, is fed into the plunger chamber 28, through a valve57 in screw plug 25, so as to provide a force tending to extend thedevice.

It will be apparent that, when the non-return valve ball 47 is seated,inward movement of the plunger 17 is prevented by the trapping of liquidin the annular space 43 in the cylinder except that, when the device isfully extended, a small flow of liquid can take place through the radialbores 51 in the tubular stem, but any such flow is almost immediatelystopped if inward movement of the plunger occurs, by the packing ring 33in the plunger end wall 23 covering the said bores, so that nosubstantial movement can take place. The

the compressed gas, or by applying an external extending force.

With the telescopic position adjusting device mounted on an aircraftseat as shown in FIG. 1, rearward tilting of the seat back 12 ispositively prevented when the non-return valve ball 47 is seated and canbe effected only by unseating the said non-return valve ball, whereasmovement of the seat back towards the substantially upright position canbe effected by the force of the compressed gas in the chamber 28 if thenon-return valve ball 47 is unseated, or can be effected without openingthe non-return valve by applying a force to the seat back itself. Thus,an occupant of the seat can adjust its position in either direction bymanipulating the non-return valve and leaning back on, or taking hisweight off, the seat back, but a person wishing to restore a seat backor seat backs to the substantially upright position, for example afterpassengers have disembarked from an aircraft, can do this merely bypushing or pulling on the seat backs.

The small radial bores 38 in the tubular stem 31, when the device isfully extended, allow liquid to pass between the chamber 29 in theplunger 17 and the annular space 43 in the cylinder. Thus if, when theseat back is moved towards the upright position by a manual pull or pushapplied thereto, the pressure difference across the valve ball 47 is notsufficient to unseat it, and liquid cannot return to the annular space43 through the valve, cavitation will occur in the said annular space 43until the device is fully extended, and liquid will then flow throughthe radial bores 38 until the said annular space 43 is refilled. Flow ofliquid can also take place through the radial bores 38 from the annularspace 43 to the chamber 29 or vice versa when the device is fullyextended to compensate for changes of the liquid volume due to expansionor contraction resulting from temperature changes.

FlG. 3 shows a modified arrangement of means for adjusting the stroke ofthe position adjusting device. A sleeve 58 is mounted on the plunger 17and is located against axial movement thereon by any suitable means, thesleeve 58, when the position adjusting device is fully extended,overlapping the adjacent end of the cylinder 16 as shown, and theoverlap increasing as the device is contracted. A stepped aperture 59 isformed in the sleeve 58, and a radial projection 61 on the cylinderextends into the aperture. The sleeve 58 is rotatable on the plunger 17to bring any one of the steps 62 in the aperture into line with theprojection 61, so that the inward stroke of the plunger is limited byengagement of the projection 61 with the step with which it is aligned.

The sleeve may be held in any angular position to which it is set by aball detent 63 located in a hole in the sleeve 58 and urged by acircumferential spring clip 64 into any one of a plurality of angularlyspaced notches 65 in the plunger 17.

It will be understood that the sleeve 58 may be mounted on the cylinder16 to co-operate with a projection similar to the projection 61 on theplunger 17.

I claim:

1. A telescopic position adjusting device comprising a cylinder having aclosed end and an open end, a hollow plunger with a centrally aperturedend wall slidably extending into said cylinder, the other end wall ofsaid plunger being closed and disposed outside of said cylinder, afloating piston disposed in said plunger and dividing it into a gaschamber filled with compressed gas adjacent its closed end wall andfirst liquid chamber adjacent its apertured end wall, a tubular memberdisposed in said cylinder having one end extending through saidapertured end wall and in communication with said liquid chamber, flangemeans on the other end of said tubular member, clip means abutting saidflange means to maintain it abutting said cylinder closed end wall, boremeans in said cylinder closed end wall in communication with saidtubular member, the inner surface of 20 said cylinder surrounding saidtubular member forming a second annular liquid chamber, diametral boremeans in said cylinder closed end wall in communication with said boremeans, a valve ball seat in said diametral bore means in communicationwith said bore means, other passage means in the cylinder closed endwall in communication with said annular liquid chamber and saiddiametral bore means, a non-return ball valve in said 6 diametral boremeans adapted to seat on said seatto cut off communication between saidfirst liquid and second liquid chambers, biasing means in said diametralbore means normally maintaining said valve seated,

and pin means operatively connected to said ball valve to unseat it. I

2. The device of claim 1 wherein said tubular member has stop meanslimiting outward movement of said plunger.

3. The device of claim 2 wherein stroke adjusting means are provided forlimiting the stroke of said plunger.

4. The device of claim 3, wherein the stroke adjusting means comprise asleeve surrounding and having screw-threaded engagement with thecylinder and an annular stop surface on the plunger to co-operate withthe end of said sleeve, releasable locking means being provided to holdthe sleeve against rotation.

5. The device of claim 3, wherein the stroke adjusting means comprise asleeve axially movable with one of the relatively axially movablemembers constituted by the cylinder and plunger and having a steppedaperture therein, a radial projection on the other of said membersextending into said aperture, and means for selectively positioning saidsleeve in the rotational sense to align the radial projection with anyone of the steps in the aperture.

1. A telescopic position adjusting device comprising a cylinder having aclosed end and an open end, a hollow plunger with a centrally aperturedend wall slidably extending into said cylinder, the other end wall ofsaid plunger being closed and disposed oUtside of said cylinder, afloating piston disposed in said plunger and dividing it into a gaschamber filled with compressed gas adjacent its closed end wall andfirst liquid chamber adjacent its apertured end wall, a tubular memberdisposed in said cylinder having one end extending through saidapertured end wall and in communication with said liquid chamber, flangemeans on the other end of said tubular member, clip means abutting saidflange means to maintain it abutting said cylinder closed end wall, boremeans in said cylinder closed end wall in communication with saidtubular member, the inner surface of said cylinder surrounding saidtubular member forming a second annular liquid chamber, diametral boremeans in said cylinder closed end wall in communication with said boremeans, a valve ball seat in said diametral bore means in communicationwith said bore means, other passage means in the cylinder closed endwall in communication with said annular liquid chamber and saiddiametral bore means, a non-return ball valve in said diametral boremeans adapted to seat on said seat to cut off communication between saidfirst liquid and second liquid chambers, biasing means in said diametralbore means normally maintaining said valve seated, and pin meansoperatively connected to said ball valve to unseat it.
 2. The device ofclaim 1 wherein said tubular member has stop means limiting outwardmovement of said plunger.
 3. The device of claim 2 wherein strokeadjusting means are provided for limiting the stroke of said plunger. 4.The device of claim 3, wherein the stroke adjusting means comprise asleeve surrounding and having screw-threaded engagement with thecylinder and an annular stop surface on the plunger to co-operate withthe end of said sleeve, releasable locking means being provided to holdthe sleeve against rotation.
 5. The device of claim 3, wherein thestroke adjusting means comprise a sleeve axially movable with one of therelatively axially movable members constituted by the cylinder andplunger and having a stepped aperture therein, a radial projection onthe other of said members extending into said aperture, and means forselectively positioning said sleeve in the rotational sense to align theradial projection with any one of the steps in the aperture.